[bug#68325] sanity.m4: a millisecond is too fast?

[Zack Weinberg]

On Mon, Jan 8, 2024, at 7:44 AM, Karl Berry wrote:
> The plethora of bug reports from the last pretest make me believe that
> many systems simply cannot (currently) reliably handle a millisecond
> difference in mtime.
...
> My current idea is to only try for a hundredth of a second.
...
> The whole idea of the am test command $sleep seems like a
> bogus workaround to me. On the other hand, failing a true fix, I think
> it needs to be added in many more places, with the advent of subsecond
> mtimes. Debugging all this is nowhere on my list :(.
>
> Anyway, if anyone has any ideas about how to better proceed, please
> speak up.

Nick Bowler had a promising suggestion, recorded in 
https://savannah.gnu.org/support/?110989 , but I am still traveling and won't 
be able to work on it until next week. In the meantime, your patch should at 
least give us some data on whether the problem really is timestamps.

zw